Yield measurement and Monte Carlo correction of CPDG neutron generator

It is useful to obtain the exact neutron yield and distribution of a portable neutron generator. In this paper, the neutron yield of a K400 accelerator D-D neutron source under conditions of 160 kV and 25 uA is 1.69 × 106 ± 4.1 × 104 n/s, which is calibrated using the associated proton method. A long counter consisting of a 3He counter surrounded by a paraffin cylinder was used as secondary standard after efficiency calibration using a K400 accelerator. The Monte Carlo method is then used to evaluate the distribution change of emitted neutrons from each surface of the CPDG caused by its structural materials. Energy spectrum distortion and angle distribution distortion of emitted neutrons are studied. Simulation results show that the proportion of the forward neutron is reduced and the proportion of the lateral neutron is increased. The number of neutron transporting into the counter has been reduced by 28.1%, 28.4%, 29.8%, 29.0%, 28.7%, and 28.0% for acceleration voltages of 90 kV, 100 kV, 110 kV, 120 kV, 130 kV, and 160 kV, respectively. In addition, the respective yield correction factors caused by structural materials are 1.36, 1.38, 1.38, 1.34, 1.37, and 1.39. The neutron yield of the CPDG is 1.28 × 106 and 1.75 × 106 before and after Monte Carlo correction when working at conditions of 130 kV and 600 μA. The total uncertainty of this result is approximately 6%.